Energy Expenditure in Free-Living Japanese People with Obesity and Type 2 Diabetes, Measured Using the Doubly-Labeled Water Method

We determined the total energy expenditure (TEE) of healthy overweight or obese people, and those with impaired glucose tolerance and/or impaired fasting glycemia (IGT/IFG), or type 2 diabetes (T2DM) using the doubly-labeled water method. As a second purpose, we compared the measured TEE with the target energy intake recommended in the treatment guidelines for diabetes. The participants were normal glucose tolerance (NGT), and IGT/IFG (n=11) and T2DM (n=9) patients, who were 50-59 y and had a body mass index >25 kg/m². The median TEE/body mass (BM) values were 32.6, 33.3, and 34.4 kcal/kg BM and the TEE/target BM values (target BM: BM at a BMI of 22 kg/m²) were 43.7, 50.2, and 46.5 kcal/kg target BM for each group, respectively, and did not differ significantly among them. Obese Japanese participants with T2DM in this study had lower TEE/BM than previously studied in non-obese participants with T2DM. In IGT/IFG or T2DM patients, if 30 kcal/kg target BM was used as the energy coefficient, on the basis of the treatment guidelines, the difference between TEE and the target energy intake would be -1,174±552 kcal (-38±11%). When 35 kcal/kg target BM was used as the energy coefficient, the difference between TEE and the target energy intake would be -877±542 kcal (-27±13%). Thus, the energy coefficients used to estimate target energy intake during lifestyle modification in obese/overweight patients with T2DM are considered to be quite low during the first step of diet therapy.

Vegetable Intake at Breakfast and Associated Factors among Young Adults in Japan

In Japan, the amount of vegetable intake in young adults, especially at breakfast, is low. We aimed to examine the factors associated with vegetable intake at breakfast among young adults. In 2016, a self-administered questionnaire survey was conducted at a Japanese university. The questionnaire measured the frequency of ≥70 g vegetable intake at breakfast, lifestyle, eating habits, environmental factors, knowledge and attitudes (including the variable "Perceived behavior control (PBC)", from the Theory of Planned Behavior). The data of 1,455 male students who usually ate breakfast were analyzed. They were divided into two groups based on the median of the frequency of vegetable intake and the above factors were compared using a chi-squared test by living condition. The significant factors were subsequently entered into a logistic regression analysis as independent variables. Eating breakfast with family or friends and PBC were positively associated with vegetable intake in students living with their family. Often doing one's own cooking, having knowledge about a well-balanced diet, and PBC were positively associated with vegetable intake in students living alone. Along with PBC, different factors pertaining to an individual's living condition may need to be considered to increase vegetable intake at breakfast.

Decreased number of days of fever detection and duration of fever with continuous intake of a fermented milk drink: a randomized, double-blind, placebo-controlled study of elderly nursing home residents

We conducted a randomized, double-blind, placebo-controlled parallel study to investigate the effects of a fermented milk on elderly nursing home residents. Eighty-eight participants each drank one bottle of fermented milk containing Lactobacillus casei strain Shirota, or a placebo, on a daily basis for 6 months in winter. Peripheral blood, saliva, fecal samples, and clinical data were analyzed to assess the milk’s efficacy. Fermented milk consumption was associated with a significant decrease in the number of days on which fever was detected and the mean duration of fever compared with these values in the placebo group. No significant differences were observed in other biological parameters. Continuous intake of this fermented milk could be beneficial for the elderly in terms of suppressing the number of days of detection of fever and the duration of fever, which usually increase in winter.

Effects of 1-year weight loss intervention on abdominal skeletal muscle mass in Japanese overweight men and women

BACKGROUND AND OBJECTIVES

Limited information is available on how weight loss intervention programs affect skeletal muscle mass especially in trunk.

METHODS AND STUDY DESIGN

A total of 235 overweight Japanese men and women aged 40-64 years with a body mass index of 28.0 to 44.8 kg/m2 participated in this randomized controlled intervention study. They were randomly divided into a lifestyle intervention group and control group. Before and after the one-year lifestyle intervention for weight loss an abdominal transverse image was acquired by computed tomography. The cross-sectional areas (CSAs) of visceral fat, subcutaneous fat, and skeletal muscle of rectus abdominis, abdominal oblique, iliopsoas, and erector spinae muscle were calculated.

RESULTS

The body weight changed by approximately -5% in the intervention groups. The corresponding values for subcutaneous fat and visceral fat CSAs were -10.8 to -17.5% in both sexes. The reductions observed in skeletal muscle CSAs were significantly less (-6.0% and -7.2% in the men and women intervention groups respectively) than those in fat tissue CSAs. The CSA of each of the four skeletal muscle groups also significantly decreased; however, after adjustments for body weight at each time point, only reductions in the iliopsoas muscle in both sex and abdominal oblique muscles in men remained significant.

CONCLUSIONS

The lifestyle weight loss intervention might reduce the relative amount of the abdominal skeletal muscles especially in iliopsoas muscle.

[Cross-sectional association of the number of neighborhood facilities assessed using postal code with objectively measured physical activity: the Saku cohort study]

Objectives The aim of this study was to examine the association between the number of neighborhood facilities that were assessed according to postal code and objectively measured physical activity by using an accelerometer in community-dwelling Japanese people.Methods The participants included 1,274 Japanese people aged 30-84 years from the Saku cohort study. As neighborhood facilities related to physical activity, we extracted information regarding train stations, supermarkets/convenience stores, postal offices/banks, hospitals/clinics, public offices/community centers, cultural facilities/public children's houses, parks, and sports facilities by using each participant's postal code from the online version of the iTownPages directory published by Nippon Telegraph and Telephone Corporation (NTT) and the official homepage of the Saku City Government Office. We measured each participant's physical activity level using an accelerometer, and calculated the average daily step count and the average weekly period of moderate-to-vigorous intensity (≥3 metabolic equivalents of tasks [METs]) physical activity. The association between two selected physical activity-related variables and the numbers of eight types of neighborhood facilities were analyzed by multivariate logistic regression analysis for people aged 30-64 years and for those aged over 65 years.Results On multivariate logistic regression analysis, meeting the 23 METs h/week of moderate-to-vigorous intensity physical activity was significantly and positively associated with the number of supermarkets/convenience stores in the neighborhood in both age groups. In addition, meeting the desired daily step count outlined in the Japanese National Health Promotion guidelines was positively related to the number of postal offices/banks for people aged over 65 years.Conclusion The results of this study suggest that a sufficient number of neighborhood facilities (i.e., stores, banks, and postal offices) is closely associated with the promotion of physical activity.

Perceptions and practices of commensality and solo-eating among Korean and Japanese university students: A cross-cultural analysis

BACKGROUND/OBJECTIVES

Commensality, eating together with others, is a major representation of human sociality. In recent time, environments around commensality have changed significantly due to rapid social changes, and the decline of commensality is perceived as a serious concern in many modern societies. This study employs a cross-cultural analysis of university students in two East Asian countries, and examines cross-cultural variations of perceptions and actual practices of commensality and solo-eating.

SUBJECTS/METHODS

The analysis was drawn from a free-list survey and a self-administrative questionnaires of university students in urban Korea and Japan. The free-listing survey was conducted with a small cohort to explore common images and meanings of commensality and solo-eating. The self-administrative questionnaire was developed based on the result of the free-list survey, and conducted with a larger cohort to examine reasons and problems of practices and associated behaviors and food intake.

RESULTS

We found that Korean subjects tended to show stronger associations between solo-eating and negative emotions while the Japanese subjects expressed mixed emotions towards the practice of solo-eating. In the questionnaire, more Korean students reported they prefer commensality and tend to eat more quantities when they eat commensally. In contrast, more Japanese reported that they do not have preference on commensality and there is no notable difference in food quantities when they eat commensally and alone. Compared to the general Korean cohort finding, more proportion of overweight and obese groups of Korean subjects reported that they tend to eat more when they are alone than normal and underweight groups. This difference was not found in the overweight Japanese subjects.

CONCLUSION

Our study revealed cross-cultural variations of perceptions and practices of commensality and solo-eating in a non-western setting.

Tks5 activation in mesothelial cells creates invasion front of peritoneal carcinomatosis

Scirrhous gastric cancer is frequently associated with peritoneal dissemination, and the interaction of cancer cells with peritoneal mesothelial cells (PMCs) is crucial for the establishment of the metastasis in the peritoneum. Although cells derived from PMCs are detected within tumors of peritoneal carcinomatosis, how PMCs are incorporated into tumor architecture is not understood. The present study shows that PMCs create the invasion front of peritoneal carcinomatosis, which depends on activation of Tks5 in PMCs. In peritoneal tumor implants, PMCs represent majority of cells located at the invasive edge of the cancer tissue. Exogenously implanted PMCs and host PMCs aggressively invade into abdominal wall upon the peritoneal inoculation of cancer cells, and PMCs locate ahead of cancer cells in the direction of invasion. Tks5, a substrate of Src kinase, is predominantly expressed in the PMCs of cancer tissue, and promotes the invasion of PMCs and cancer cells. Expression and activation of Tks5 was induced in PMCs following their exposure to gastric cancer cells, and increased Tks5 expression was detected in PMCs located at the invasion front. Reduced Tks5 expression in PMCs blocked PMC invasion, which in turn prevents cancer cell invasion both in vitro and in vivo. The peritoneal dissemination of gastric cancer was significantly increased by mixing cancer cells and PMCs, and was suppressed by knockdown of Tks5 in PMCs. These results suggest that cancer-activated PMCs create invasion front by guiding cancer cells. Signaling leading to Tks5 activation in PMCs may be a suitable therapeutic target for prevention of peritoneal carcinomatosis.

Preproghrelin gene polymorphisms in obese Japanese: Association with diabetes mellitus in men and with metabolic syndrome parameters in women

SUMMARY

Preproghrelin gene polymorphisms (SNPs) are possible predisposing factors to obesity and metabolic syndrome. We analysed SNPs in obese Japanese individuals and studied the correlation with diabetes and metabolic syndrome. We recruited 235 subjects (BMI > 28.3) from individuals undergoing periodic medical check-up at Saku Central Hospital. Their SNPs were genotyped using PCR-RFLP method. Frequencies of 5 SNPs in the preproghrelin gene -1500C>G (rs3755777), -1062G>C (rs26311), -994C>T (rs26312), Leu72Met (+408C>A) (rs696217), and +3056T>C (rs2075356) were compared with healthy individuals (data from HapMap Project or Asian population studies). Associations between these SNPs and clinical parameters were investigated. The phenotypes evidently differed between men and women. In men, higher fasting glucose and HbA1c values were observed in the +3056C/C minor homozygotes without leptin or insulin accumulation. The +408C -- +3056C haplotype was more frequent in the diabetic subgroup, in which diagnosis was based on fasting glucose, 75gOGTT, and HbA1c values, than normal subgroup. In contrast, in women, a significant correlation was observed between fat metabolism and obesity. The -1062C/C minor homozygotes had higher values of C-peptide, insulin, total and visceral fat area, waist circumference and BMI. The 72Met/Met minor homozygotes showed reduced leptin, total, HDL and LDL cholesterol concentrations and increased value of visceral fat area. Further, in the other SNPs, the minor homozygotes showed a similar trend, and the heterozygotes had intermediate values. Preproghrelin gene polymorphisms in obese Japanese may be predisposing factors to diabetes mellitus in men and to obesity via aberrant fat metabolism in women.:

Low-molecular-weight adiponectin and high-molecular-weight adiponectin levels in relation to diabetes

OBJECTIVE

To evaluate the association between adiponectin complexes (high-molecular-weight [HMW], middle-molecular-weight [MMW], and low-molecular-weight [LMW] adiponectin) and diabetes.

DESIGN AND METHODS

We conducted a case-control study, based on a cohort in Saku, Japan. Among 2565 participants, 300 participants with diabetes and 300 matched controls (430 men and 170 women) were analyzed.

RESULTS

After adjusting for age, physical activity, hypertension, family history, alcohol use, smoking, and menopausal status, total, HMW, and LMW, but not MMW adiponectin levels were inversely associated with diabetes: total adiponectin, odds ratio comparing the highest with the lowest quartiles, 0.46 (95% confidence interval, 0.25-0.82; P for trend = 0.046); HMW, 0.40 (95%CI, 0.22-0.72; P = 0.046); MMW, 1.04 (95%CI, 0.60-1.77; P = 0.81); and LMW, 0.51 (95%CI, 0.29-0.89; P = 0.01). The associations between total and HMW adiponectin and diabetes attenuated after adjustment for BMI (P = 0.15 and 0.13, respectively), but LMW remained (P = 0.04). When stratified by sex, LMW adiponectin levels were associated with diabetes in men only. None of the associations were significant after adjustment for HOMA-IR.

CONCLUSIONS

Decreased LMW, total, and HMW adiponectin levels are associated with diabetes. These associations may be secondary to adiposity or insulin resistance.

Asporin activates coordinated invasion of scirrhous gastric cancer and cancer-associated fibroblasts

Scirrhous gastric cancer, which has the worst prognosis among the various types of gastric cancer, is highly invasive and associated with abundant stromal fibroblasts. Although cancer-associated fibroblasts (CAFs) have been proposed to generate a tumor-supportive extracellular matrix that promotes the expansion of this type of cancer, the molecular mechanisms by which CAFs assist cancer cells are not yet fully understood. Here, we show for the first time that Asporin, a small leucine-rich proteoglycan (SLRP), is predominantly expressed in CAFs, and has essential roles in promoting co-invasion of CAFs and cancer cells. CAFs of scirrhous gastric cancer possess high potential for invasion, and invasion by CAFs frequently proceeded invasion by cancer cells, both in vitro and in vivo. Expression of Asporin was induced in fibroblasts by exposure to gastric cancer cells. Asporin secreted from CAFs activates Rac1 via an interaction with CD44 and promotes invasion by CAFs themselves. Moreover, Asporin promoted invasion by neighboring cancer cells, via paracrine effects mediated by activation of the CD44-Rac1 pathway. These results suggest that Asporin is a unique SLRP that promotes progression of scirrhous gastric cancer and is required for coordinated invasion by CAFs and cancer cells. Therefore, Asporin may represent a new therapeutic target molecule for the development of drugs aimed at manipulating the cancer microenvironment.

Validity of diabetes self-reports in the Saku diabetes study

BACKGROUND

Diabetes is an important risk factor for cardiovascular disease, certain types of cancer, and death, and self-reports are one of the most convenient methods for ascertaining diabetes status. We evaluated the validity of diabetes self-reports among Japanese who participated in a health checkup.

METHODS

Self-reported diabetes was cross-sectionally compared with confirmed diabetes among 2535 participants aged 28 to 85 years in the Saku cohort study. Confirmed diabetes was defined as the presence of at least 1 of the following: fasting plasma glucose (FPG) level of 126 mg/dL or higher, 2-hour post-load glucose (2-hPG) level of 200 mg/dL or higher after a 75-gram oral glucose tolerance test, glycated hemoglobin (HbA1c) level of 6.5% or higher, or treatment with hypoglycemic medication(s).

RESULTS

Of the 251 participants with self-reported diabetes, 121 were taking hypoglycemic medication(s) and an additional 69 were classified as having diabetes. Of the 2284 participants who did not self-report diabetes, 80 were classified as having diabetes. These data yielded a sensitivity of 70.4%, a specificity of 97.3%, a positive predictive value of 75.7%, and a negative predictive value of 96.5%. The frequency of participants with undiagnosed diabetes was 3.0%. Of these, 64.2% had FPG within the normal range and were diagnosed by 2-hPG and/or HbA1c.

CONCLUSIONS

Our findings provide additional support for the use of self-reported diabetes as a measure of diabetes in epidemiologic studies performed in similar settings in Japan if biomarker-based diagnosis is difficult.

Reduction in adiposity, β-cell function, insulin sensitivity, and cardiovascular risk factors: a prospective study among Japanese with obesity

Background

A reduction in adiposity may be associated with an improvement in insulin sensitivity and β-cell function as well as cardiovascular disease (CVD) risk factors; however, few studies have investigated these associations in a longitudinal setting.

Methods

To investigate these associations over a 1-year period, we conducted an observational analysis of 196 Japanese subjects with obesity in the Saku Control Obesity Program. We investigated the relations between changes in adiposity (body mass index [BMI], waist circumference, subcutaneous fat area [SFAT], and visceral fat area [VFAT]) and changes in HbA1c, fasting plasma glucose (FPG), insulin sensitivity index (ISI), the homeostasis model assessment β cell function (HOMA-β), lipids, and blood pressure.

Results

All adiposity changes were positively associated with HbA1c and FPG changes. Reductions in BMI and VFAT were associated with HOMA-β reduction. Reductions in all adiposity measures were associated with an improvement in the ISI. Changes in most adiposity measures were positively associated with changes in blood pressure and lipid levels, except for LDL.

Conclusion

The present findings provide additional supportive evidence indicating that a reduction in adiposity may lead to an improvement in insulin sensitivity and the reduction of CVD risk factors in obese individuals.

Associations of sex hormone-binding globulin and testosterone with diabetes among men and women (the Saku Diabetes study): a case control study

BACKGROUND

Sex hormone-binding globulin (SHBG) levels and sex hormones have been implicated in the pathogenesis of type 2 diabetes and cardiovascular diseases. As fatty liver has been suggested to be a major determinant of SHBG levels, we examined whether the associations of SHBG and testosterone with diabetes were independent of fatty liver.

METHODS

We conducted a case-control study that included 300 diabetes cases (215 men and 85 women) and 300 matched controls from the Saku cohort study. Diabetes was defined by either fasting plasma glucose levels ≥126 mg/dL, 2-h post-load glucose levels ≥200 mg/dL after a 75 g oral glucose tolerance test, or diabetes diagnosed by physicians. We fitted conditional logistic regression models to examine the associations between SHBG and total testosterone levels with diabetes by sex. To evaluate the impact of fatty liver, we used the fatty liver index (FLI), a validated measure derived from serum triglyceride levels, body mass index (BMI), waist circumference, and γ-glutamyltransferase levels.

RESULTS

After adjusting for age, family history of diabetes, smoking, physical activity, BMI, and FLI, SHBG levels were inversely associated with diabetes among women (odds ratio [OR] comparing the highest with the lowest quartiles, 0.13 [95% confidence interval {CI}, 0.02-0.96]), but not among men. Similar patterns were observed in a subgroup analysis restricted to postmenopausal women"(OR, 0.12 [95% CI, 0.01-1.17]). In contrast, testosterone levels were inversely associated with diabetes among men (OR, 0.45 [95% CI, 0.23-0.89]), but not among women.

CONCLUSIONS

Our findings suggest that SHBG in women and testosterone in men may be inversely associated with diabetes.

Dietary glycemic index and glycemic load in relation to HbA1c in Japanese obese adults: a cross-sectional analysis of the Saku Control Obesity Program

BACKGROUND

Dietary glycemic index or load is thought to play an important role in glucose metabolism. However, few studies have investigated the relation between glycemic index (GI) or load (GL) and glycemia in Asian populations. In this cross-sectional analysis of a randomized controlled trial, the Saku Control Obesity Program, we examined the relation between the baseline GI or GL and glycemia (HbA1c and fasting plasma glucose [FPG] levels), insulin resistance (HOMA-IR), β-cell function (HOMA-β), and other metabolic risk factors (lipid levels, diastolic and systolic blood pressure, and adiposity measures).

METHODS

The participants were 227 obese Japanese women and men. We used multiple linear regression models and logistic regression models to adjust for potential confounding factors such as age, sex, visceral fat area, total energy intake, and physical activity levels.

RESULTS

After adjustments for potential confounding factors, GI was not associated with HbA1c, but GL was positively associated with HbA1c. For increasing quartiles of GI, the adjusted mean HbA1c were 6.3%, 6.7%, 6.4%, and 6.4% (P for trend = 0.991). For increasing quartiles of GL, the adjusted mean HbA1c were 6.2%, 6.2%, 6.6%, and 6.5% (P for trend = 0.044). In addition, among participants with HbA1c ≥ 7.0%, 20 out of 28 (71%) had a high GL (≥ median); the adjusted odds ratio for HbA1c ≥ 7.0% among participants with higher GL was 3.1 (95% confidence interval [CI] = 1.2 to 8.1) compared to the participants with a lower GL (

CONCLUSIONS

Our findings suggest that participants with poor glycemic control tend to have a higher GL in an obese Japanese population.

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Affiliation(s)

Maki Goto Department of Diabetes Research, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan.
Akemi Morita
Atsushi Goto
Satoshi Sasaki
Naomi Aiba
Takuro Shimbo
Yasuo Terauchi
Motohiko Miyachi
Mitsuhiko Noda
Shaw Watanabe

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What behaviors are important for successful weight maintenance?

Purpose. To examine behavioral factors related to successful weight maintenance. Methods. Subjects were 90 middle-aged participants who attended a weight loss program and were followed for one year. The subjects were classified into either successful weight maintainers (maintained a weight loss of 5% or more from their initial weight for one year) (SWM) or unsuccessful weight maintainers (USWM), and weight control practice, stress, obstacles, support, and self-efficacy during the program and follow-up period were compared. Results. SWM had mean loss of 12% from their initial weight during the program. They showed a greater improvement in their regularity of eating, walked more, and felt less stress regarding their increased physical activity than the USWM. During the follow-up period, significantly more SWM participants had self-efficacy (for measuring weight, practicing dietary objective, and assessing the practice and keeping records), actually kept records and measured weight more than the USWM participants. In contrast, more USWM participants felt stress about measuring weight. Conclusion. In addition to a substantial initial weight loss due to an increased amount of physical activity, having a higher self-efficacy and consistently keeping records of one's activities, as well as regularly weighing themselves, may be important for successful weight maintenance.

Behavioral change during weight loss program and one-year follow-up: Saku Control Obesity Program (SCOP) in Japan

This study evaluated effects of a behavioral approach which placed emphasis on tailored behavior counseling, diet, weight loss and weight maintenance. A one-year randomized controlled trial was conducted among 235 overweight/obese adults in Japan. The intervention group (n=119) received individual-based counseling using a behavioral approach and the changes made in the diet and physical activity were dependent on each participant as much as possible. One year later, the intervention group lost significantly more weight than the control group (-5.0 kg vs. 0.1 kg for men and -3.9 kg vs. -0.2 kg for women). Compared to the control group, the male intervention group reduced overall energy, cereals and dairy products consumption significantly, while increasing green and yellow vegetable intake, and the female intervention group significantly reduced intake of dairy products. Regarding behaviors, both male and female intervention groups increased the number of walking steps and women improved their irregular eating habits compared to those in the control groups. Behavior changes were related to weight loss; participants who maintained the action/maintenance stage or moved to later stages lost significantly more weight than participants who remained in the pre-contemplation/contemplation/preparation stages or regressed to earlier stages. After one-year follow-up, the intervention group maintained significantly lower weights, lower energy intakes and improvements in irregular eating habits. Our behavioral approach led to diet and behavior modification, weight loss and maintenance. Because modified variables differed between men and women, gender-specific approaches may be necessary.

Caffeine abolishes the ultraviolet-induced REV3 translesion replication pathway in mouse cells

When a replicative DNA polymerase stalls upon encountering a photoproduct on the template strand, it is relieved by other low-processivity polymerase(s), which insert nucleotide(s) opposite the lesion. Using an alkaline sucrose density gradient sedimentation technique, we previously classified this process termed UV-induced translesion replication (UV-TLS) into two types. In human cancer cells or xeroderma pigmentosum variant (XP-V) cells, UV-TLS was inhibited by caffeine or proteasome inhibitors. However, in normal human cells, the process was insensitive to these reagents. Reportedly, in yeast or mammalian cells, REV3 protein (a catalytic subunit of DNA polymerase ζ) is predominantly involved in the former type of TLS. Here, we studied UV-TLS in fibroblasts derived from the Rev3-knockout mouse embryo (Rev3KO-MEF). In the wild-type MEF, UV-TLS was slow (similar to that of human cancer cells or XP-V cells), and was abolished by caffeine or MG-262. In 2 cell lines of Rev3KO-MEF (Rev3^−/−p53^−/−), UV-TLS was not observed. In p53KO-MEF, which is a strict control for Rev3KO-MEF, the UV-TLS response was similar to that of the wild-type. Introduction of the Rev3 expression plasmid into Rev3KO-MEF restored the UV-TLS response in selected stable transformants. In some transformants, viability to UV was the same as that in the wild-type, and the death rate was increased by caffeine. Our findings indicate that REV3 is predominantly involved in UV-TLS in mouse cells, and that the REV3 translesion pathway is suppressed by caffeine or proteasome inhibitors.

Rev1, Rev3, or Rev7 siRNA Abolishes Ultraviolet Light-Induced Translesion Replication in HeLa Cells: A Comprehensive Study Using Alkaline Sucrose Density Gradient Sedimentation

When a replicative DNA polymerase stalls upon encountering a lesion on the template strand, it is relieved by other low-processivity polymerase(s), which insert nucleotide(s) opposite the lesion, extend by a few nucleotides, and dissociate from the 3'-OH. The replicative polymerase then resumes DNA synthesis. This process, termed translesion replication (TLS) or replicative bypass, may involve at least five different polymerases in mammals, although the participating polymerases and their roles have not been entirely characterized. Using siRNAs originally designed and an alkaline sucrose density gradient sedimentation technique, we verified the involvement of several polymerases in ultraviolet (UV) light-induced TLS in HeLa cells. First, siRNAs to Rev3 or Rev7 largely abolished UV-TLS, suggesting that these 2 gene products, which comprise Polζ, play a main role in mutagenic TLS. Second, Rev1-targeted siRNA also abrogated UV-TLS, indicating that Rev1 is also indispensable to mutagenic TLS. Third, Polη-targeted siRNA also prevented TLS to a greater extent than our expectations. Forth, although siRNA to Polι had no detectable effect, that to Polκ delayed UV-TLS. To our knowledge, this is the first study reporting apparent evidence for the participation of Polκ in UV-TLS.

Observation of an energetic-particle-driven instability in the wall-stabilized high-beta plasmas in the JT-60U tokamak

We have observed a bursting mode in the high-beta plasmas above the ideal beta limit without a conducting wall. The mode frequency is chirping down as the mode amplitude increases, and its initial value is close to the precession frequency of the trapped energetic particle from the perpendicular neutral beams. The mode structure is radially extended with a peak around the q = 2 surface. This mode can finally trigger the resistive wall mode (RWM) despite enough plasma rotation for RWM stabilization. It is concluded that the mode is driven by trapped energetic particles. The mode is attributed to the interaction between the trapped energetic particles and a marginally stable mode in the wall-stabilized high-beta_{N} region.

Food safety and food labeling from the viewpoint of the consumers

Distrust of food safety has grown among the Japanese people after the occurrence of bovine spongiform encephalitis (BSE) in 2001. The Food Safety Commission was formed under the Cabinet Office and made a network among the ministries. The newly-established Consumer Agency may strengthen the quick response to emergencies. Shoku-iku (food and dietary education) Law is being implemented by the Cabinet Office with cooperation from relevant ministries and NGOs. Food Sanitation Law and Health Promotion Law are briefly explained, and the necessity of functional nutriology for non-nutrient biologically active substances is described. With regard to public health nutrition, a new food label showing energy balance and antioxidant unit (AOU) as a surrogate marker of fruit and vegetables has been developed for tailor-made nutrition which makes it easy to for individuals to control energy intake.

Identification of a low plasma-rotation threshold for stabilization of the resistive-wall mode

The plasma rotation necessary for stabilization of resistive-wall modes (RWMs) is investigated by controlling the toroidal plasma rotation with external momentum input by injection of tangential neutral beams. The observed threshold is 0.3% of the Alfvén velocity and much smaller than the previous experimental results obtained with magnetic braking. This low critical rotation has a very weak beta dependence as the ideal wall limit is approached. These results indicate that for large plasmas such as in future fusion reactors with low rotation, the requirement of the additional feedback control system for stabilizing RWM is much reduced.

Analysis of the NPHP genes in two Japanese patients with suspected sporadic juvenile or adolescent nephronophthisis

BACKGROUND

Mutations in 3 genes (NPHP1, NPHP3 and NPHP4) have been identified in patients with juvenile or adolescent nephronophthisis (NPHP) without extrarenal involvement, mainly in patients from western countries. In this study, we analyzed mutations in the NPHP genes of 2 Japanese patients with suspected sporadic juvenile or adolescent NPHP without extrarenal involvement.

METHODS

A renal biopsy was performed in the 2 patients. Genomic DNA was prepared from peripheral blood mononuclear cells of the patients and their family members. The above NPHP genes were examined by deletion analysis or direct automated sequencing of polymerase chain reaction-amplified DNA products.

RESULTS

Histological findings in the patients were compatible with those of NPHP. In 1 patient, we identified a novel deletion mutation including about half of exons of the NPHP1 gene. In another patient, there was no mutation in the NPHP genes examined.

CONCLUSIONS

We found a novel NPHP1 deletion in 1 patient. To our knowledge, this is the second Japanese NPHP case in which genetic diagnosis was made.

A nonsense mutation (R220X) in the alpha-galactosidase A gene causes typical Fabry disease in both genders

BACKGROUND

Fabry disease is an X-linked recessive disorder resulting from a deficiency of lysosomal alpha-galactosidase A (alpha-Gal A). Chronic renal failure is an important cause of death in patients with Fabry disease. We report on patients with Fabry disease (a hemizygous male and his mother) due to a nonsense mutation (R220X) in the alpha-Gal A gene.

METHODS

The proband, a 41-year-old man, and his 71-year-old mother presented with renal and cardiac manifestations of Fabry disease. Histological examination and molecular analysis of the alpha-Gal A gene were performed.

RESULTS

Typical histological findings of Fabry disease were observed in a renal biopsy specimen from the proband and in renal and myocardial necropsy specimens from the mother. Sequencing of a full-length alpha-Gal A cDNA from the proband indicated a C-T transition at codon 220, resulting in substitution of the predictable termination for arginine (R220X). Examination of genomic alpha-Gal A DNA revealed that the proband was a hemizygote and the mother was a heterozygous carrier for the mutation.

CONCLUSION

This is the first detailed report of family members with Fabry disease due to a nonsense mutation (R220X) in the alpha-Gal A gene. Our study indicates that this mutation causes the typical disease in both genders.

A case of secondary diabetes mellitus with acromegaly improved by pioglitazone

AIM

The acromegaly patient was diagnosed with Type 2 diabetes mellitus. His HbA1c was 10.6% and fasting blood glucose (FBG) 15.3 mmol/l. We prescribed glibenclamide (10 mg/day), but his HbA1c and FBG remained high. At this stage, treatment with short-acting insulin was instigated at a dose of 20 U/day. However, the patient's blood glucose level remained unsatisfactory. We tried using pioglitazone.

METHOD

Pioglitazone was prescribed at 30 mg/day in combination with the insulin.

RESULTS

The FBG and HbA1c value decreased to 7.2 mmol/l and 7.3%, respectively, within 2 months and insulin was discontinued. Pioglitazone alone was able to control the FBG level.

CONCLUSIONS

Pioglitazone treatment might be considered as a choice for similar cases of diabetes secondary to acromegaly.

Induction of antioxidant enzymes by FAK in a human leukemic cell line, HL-60

We have established several focal adhesion kinase (FAK) cDNA-transfected HL-60 (HL-60/FAK) cells which were highly resistant to oxidative stress-induced apoptosis. To identify target genes that are involved in HL-60/FAK cells, we performed cDNA microarray screening using apoptosis-chip. There, we identified the decrease of glutathione peroxidase (GPx). This result prompted us to investigate the changes of antioxidant enzymes. Here, we demonstrate that lipid peroxidation was suppressed after treatment with hydrogen peroxide in HL-60/FAK cells but not vector-transfected HL-60 (HL-60/Vect) cells. Furthermore, we demonstrate that HL-60/FAK cells have higher basal reactive oxygen species (ROS) levels than the parental HL-60 or HL-60/Vect cells, while ROS accumulation by hydrogen peroxide treatment was almost the same in these cells. Basal activity and mRNA expression of antioxidant enzymes, particularly of GSH reductase (GRe), phospholipid hydroperoxide glutathione peroxidase (PHGPx) were markedly elevated in HL-60/FAK cells. In contrast, GPx and catalase levels were decreased in HL-60/FAK cells. Further, a Src family kinases inhibitor, PP2, suppressed GRe and PHGPx mRNA by inactivation of FAK and c-Src in HL-60/FAK cells. These results suggest that FAK upregulates antioxidant enzymes and suppresses lipid peroxidation, resulting in the anti-apoptotic state for oxidative stress.

Simultaneous detection of hepatitis B, C, and G viral genomes by multiplex PCR method

We established a multiplex polymerase chain reaction (PCR) method for simultaneous detection of hepatitis B, C, and G viral genomes. The levels of concordance with the data obtained by conventional single PCR method were 100% for single infection, 98 to 100% for double infections, and 92% for triple infections. This method is not only suited to rapid, large-scale epidemiological screening and clinical diagnosis of those virus infections occurring alone or in combination, but is also time- and cost-effective.

Biliary excretion of copper in LEC rat after introduction of copper transporting P-type ATPase, ATP7B

Wilson's disease, an autosomal recessive disorder, is characterized by the excessive accumulation of hepatic copper that results from reduced biliary copper excretion and disturbed incorporation of copper into ceruloplasmin. The ATP7B gene, responsible for the disease, encodes a copper transporting P-type ATPase. We previously demonstrated the involvement of ATP7B in hepatic copper secretion into plasma after the introduction of ATP7B into the Long-Evans Cinnamon (LEC) rat, a rodent model of Wilson's disease. In this study we found the increased copper contents of the hepatic lysosomal fractions and bile in the LEC rats after ATP7B introduction, indicating the participation of ATP7B in the biliary excretory pathway for copper.

A major phenobarbital-inducible P450 isozyme, CYP2A14, in the Chinese hamster liver: purification, characterization, and cDNA cloning

Phenobarbital, a potent inducer of CYP2B isozyme of cytochrome P450, induces mainly CYP2A but not CYP2B in the Chinese hamster liver. A major isozyme inducible by phenobarbital was purified by column chromatography from Chinese hamster livers. This isozyme, named P450CH2A-2 and designated CYP2A14, had in the reconstituted system high activities of 7-ethoxycoumarin O-deethylase (43 nmol/min/nmol P450) and aflatoxin B1 activation and a moderate activity of testosterone 15alpha-hydroxylase and coumarin 7-hydroxylase. The N-terminal amino acid sequence of the purified protein had a high homology with those of CYP2A proteins. cDNA of this isozyme was analyzed by screening a Chinese hamster liver cDNA library with cDNA of CYP2A1 as a probe, and the obtained clone encoded a protein of 494 amino acids with a calculated molecular mass of 56.4 kDa. The N-terminal amino acid sequence of 20 residues was identical to that derived from the purified protein. The deduced amino acid sequence of the clone had a high identity with most of CYP2A proteins (>65%) and thus was designated CYP2A14. Immunoblot and Northern blot analyses demonstrated that this isozyme was induced markedly by phenobarbital but not with 3-methylcholanthrene and constitutes one of the major components in livers of phenobarbital-treated Chinese hamsters.

Nine patients with hepatocellular carcinoma surviving for more than six years after treatment, including two patients who have survived without recurrence after hepatic lobectomy

Of patients treated for hepatocellular carcinoma (HCC) accompanied by liver cirrhosis at our University Hospital between 1985 and 1990, clinical background factors in nine patients (7.0% of all patients) who survived for more than six years were examined to clarify the conditions that facilitate long-term survival. In particular, we describe two cases among these patients who have survived without the recurrence of a liver tumor for more than six years after hepatic lobectomy. In eight of nine patients, surgery was performed as the initial treatment. In seven patients, HCC was solitary and there was no portal invasion. Six patients were evaluated as Stage I according to clinical staging. Furthermore, the two patients without recurrence after treatment have been taking immunostimulators since their initial treatment until the present. The above observations suggest that surgical treatment should be considered in patients in whom hepatic reserve capacity is well maintained despite a tumor size greater than 2 cm. Subsequent recurrence should be detected earlier, and percutaneous ethanol injection therapy (PEIT) with a focus on maintaining liver function should be repeated. In addition, multi-disciplinary treatment including medication with immunostimulators is beneficial.

Mouse forkhead (winged helix) gene LUN encodes a transactivator that acts in the lung

Many transcription factors involved in the determination and maintenance of cell fates share DNA-binding motifs to form gene families. The most recently discovered evolutionarily conserved DNA-binding domain of 100 amino acids, termed the forkhead domain, emerged from a sequence comparison of the rat transcription factor HNF-3 alpha and the homeotic gene fork head of Drosophila. Here we describe the isolation of a new mouse forkhead gene named LUN. Of a total of five forkhead genes in the lung, the LUN gene was uniquely expressed in the bronchiolar epithelium and in type II pneumocytes. We found that the LUN protein has forkhead domain that is identical to the HFH8 gene and a C-terminal region that is very similar to the HFH8 gene. Based on the structural similarity of the two proteins, we investigated the structure-function relationship of the LUN protein in two kinds of promoters and found that regions C and D work differently as activation domains, namely that region C acts autonomously but region D cannot work without region C. These results suggest that the LUN gene may play an important role as a transactivator in the determination and maintenance of some types of cells in the lung.

Case report: intrahepatic portal-hepatic venous shunts associated with a huge pelvic leiomyoma

We present a case of portal-systemic encephalopathy due to intrahepatic multiple portal-hepatic venous shunts. A 71-year-old woman was admitted to our hospital because of recurrent episodes of disturbed consciousness. She showed no clinical signs of portal hypertension. Liver function was normal, except for an indocyanine green retention rate of 34% at 15 min and blood ammonia level of 282 microg/dL. Portal venography revealed dilatation of the portal vein and multiple portal-hepatic venous shunts, and a liver biopsy specimen revealed almost normal liver. Further clinical examination revealed a huge pelvic tumour. At laparotomy, two dilated veins were seen to arise from the pelvic tumour with blood flow into the mesentery. The tumour was resected successfully and a histological diagnosis of leiomyoma was made. The blood ammonia concentration decreased to the normal range postoperatively. A follow-up portal venogram demonstrated decreased portal vein dilatation and minor portal-hepatic venous shunts, considered to be congenital in origin. It is concluded that hepatic encephalopathy was produced in this patient due to an excess portal blood flow from the huge pelvic leiomyoma via the mesentery, with portosystemic shunting through pre-existent (probably congenital) intrahepatic anastomoses.

Restoration of holoceruloplasmin synthesis in LEC rat after infusion of recombinant adenovirus bearing WND cDNA

Wilson's disease, an autosomal recessive disorder, is characterized by the excessive accumulation of copper in the liver. WND (ATP7B) gene, which encodes a putative copper transporting P-type ATPase, is defective in the patients. To investigate the in vivo function of WND protein as well as its intracellular localization, WND cDNA was introduced to the Long-Evans Cinnamon rat, known as a rodent model for Wilson's disease, by recombinant adenovirus-mediated gene delivery. An immunofluorescent study and a subcellular fractionation study revealed the transgene expression in liver and its localization to the Golgi apparatus. Moreover, since the synthesis of holoceruloplasmin is disturbed in the Long-Evans Cinnamon rat, the plasma level of holoceruloplasmin, oxidase-active and copper-bound form, was examined to evaluate the function of WND protein with respect to the copper transport. Consequently, the appearance of holoceruloplasmin in plasma was confirmed by Western blot analysis and plasma measurements for the oxidase activity and the copper content. These findings indicate that introduced WND protein may function in the copper transport coupled with the synthesis of ceruloplasmin and that the Golgi apparatus is the likely site for WND protein to manifest its function.

The precore sequence of hepatitis B virus is required for nuclear localization of the core protein

The cellular localization of the precore/core and core proteins was studied by immunofluorescence following transfection of 143 thymidine kinase-negative (TK ) and Hep-G2 cells with expression constructs containing wild-type (hepatitis B e antigen [HBeAg]-positive) and precore mutant (HBeAg-negative) sequences. Precore/core constructs with the wild-type phenotype result in strong nuclear staining, while, in contrast, constructs expressing core antigen alone have strong cytoplasmic staining. These differences in the pattern of immunofluorescence staining may be caused by expression of the precore/core protein, some of which may be translocated into the nucleus, following removal of the signal peptide. In vitro translation experiments showed that the main protein products obtained in the presence of microsomal membranes were the precore/core protein and a truncated product representing the same protein without its signal peptide. Core protein expression from the precore mutant constructs was very much reduced, indicating that translational re-initiation was not very efficient. The significance of the precore/core protein being present in the nucleus is not clear, but suggests that it may be important in the replicative cycle of the virus. Finally, HBeAg produced by some of the constructs could not be detected because amino acid substitutions affected antibody-binding epitopes.

Emergence and selection of HBV variants in an anti-HBe positive patient persistently infected with quasi-species

BACKGROUND/AIMS

Infection with the hepatitis B e antigen (HBeAg) negative variant of hepatitis B virus (HBV) causes chronic liver disease characterised by occasional acute exacerbations. This virus exhibits a high prevalence of mutations in the core region. Our aim was to study the changes in the pre-core/core region of the virus in relation to exacerbations of the disease.

METHODS/RESULTS

We performed direct sequencing on DNA amplified from 7 sequential sera taken over a 5-year period from a hepatitis B surface antigen (HBsAg) and anti-HBe positive Greek patient infected with the HBeAg negative variant. The patient had chronic hepatitis with several acute exacerbation episodes and underwent interferon therapy twice. We found significant variability in the core region at different time points. To determine whether these variants were present in the initial serum sample and subsequently selected under immune pressure or whether they arose de novo during the course of the disease, we cloned the pre-core/core region from 4 sera before and after episodes of acute exacerbation. Fifteen clones from each time point were sequenced. Fourteen nucleotide mutations in the pre-core/core region were recorded, 7 (50%) of which led to amino-acid substitutions. All the amino-acid changes occurred at recognised B- and CD4+ epitopes. The cloning results indicate the presence of quasi-species in all the samples investigated. Some of the variants present as a minor population in the first sample appear to have been selected and become dominant in subsequent sera. However, the emergence of novel variants, not present at a detectable level in earlier samples, during the course of the disease, was also established. The quasi-species nature of HBV only became apparent after the cloning experiments and was not obvious from the direct sequencing results.

CONCLUSIONS

New dominant variants occurring during the course of the disease arose either by the selection of pre-existing mutants that were not detected by direct sequencing or by mutation of existing strains. All changes were located within B- and CD4+ epitopes. The continuous production and selection of variants may enable virus to evade elimination by the immune system, resulting in persistent infection.

Etiology and prognosis of cryptogenic liver cirrhosis: possible contribution of hepatitis B virus

Three female patients without type B or type C viral hepatitis, alcoholic, metabolic or autoimmune liver disease, were selected from 250 cases with histologically proven liver cirrhosis (M:F = 183:67). All three cases showed at least one positive aspect among three parameters of serum anti-HBc (RPHA, x1), HBV-DNA (gene S, nested PCR) and liver HBs and/or pre-S2 antigen (immunoperoxidase methods). Two cases may suggest a spontaneous disappearance of HBV from sera. Another case may suggest a contribution of mutant HBV which can not be detected by the routine tests. These HBV-related cirrhotic patients have done well clinically and have not been associated with hepatocellular carcinoma during the period from 6 to 12 years of follow-up when compared with 59.6% and 65.4% prevalence of hepatocarcinogenesis in type B and type C hepatitis-associated cirrhosis during the observation period of six and seven years on average, respectively.

Susceptibility of Oka varicella vaccine strain to antiviral drugs

Susceptibility of Oka varicella vaccine virus to antiherpetic drugs was determined by the effective dose for 50% plaque reduction (ED50) using cell-free virus preparation. ED50 values were 3.02 microM for acyclovir, 3.72 microM for vidarabine, 0.0035 microM for sorivudine, and 4.67 microM for penciclovir. Oka varicella vaccine virus was as susceptible to these drugs as wild-type viruses. Sensitivity of thymidine kinase (TK)-deficient virus to penciclovir and of some DNA polymerase (DPase) mutants to sorivudine suggested that these drugs might be used for the treatment of vaccine recipients, even if Oka varicella vaccine became acyclovir-resistant by mutations in the TK or DPase genes, respectively. This result encourages the wider use of Oka varicella vaccine even for immunocompromised hosts because of its attenuation and susceptibility to chemotherapeutic drugs.

The process of calcification during development of the rat tracheal cartilage characterized by distribution of alkaline phosphatase activity and immunolocalization of types I and II collagens and glycosaminoglycans of proteoglycans

The rat tracheal cartilage was shown to calcify during development. The process of calcification was characterized in terms of distribution of alkaline phosphatase (ALP) activity and alterations to immunolocalization of types I and II collagens and glycosaminoglycans of proteoglycans during the development of the tracheal cartilage, in comparison with calcification of the epiphyseal growth plate cartilage. ALP activity was not identified in the tracheal cartilage in the course of calcification, which therefore differed from that in the growth plate. The tracheal cartilage matrix was not resorbed or invaded by type I collagen during calcification. This suggests that no osteogenesis is involved in calcification of the cartilage. Immunoreactivity for type II collagen became weaker in the central region of the tracheal cartilage during development. No net loss of proteoglycans was identified with Alcian blue staining after calcification of the tracheal cartilage. Immunoreactivity for chondroitin 4-sulphate increased in the calcified tracheal cartilage, while reactivity for chondroitin 6-sulphate was weaker in the calcified area than in the surrounding uncalcified region of the tracheal cartilage. The alteration of the extracellular matrices during development may be involved in the calcification of the rat tracheal cartilage.

Processing of hepatitis B virus surface antigen expressed by recombinant Oka varicella vaccine virus

We have constructed a recombinant Oka varicella vaccine virus expressing hepatitis B virus (HBV) surface antigen (HBsAg). HBsAg was synthesized as 26K and 30K proteins in infected cells and secreted into the culture supernatant as 30K and 35K proteins. Inhibitors and glycosidase treatments, and pulse-chase labelling experiments, revealed the glycosylation process of HBsAg. The latter was synthesized as a non-glycosylated 26K protein and subjected to N-linked glycosylation to form a 30K protein with high mannose glycans. Three species of dimers composed of 26K and 30K subunits were then formed with disulphide bonds. Both subunits of the dimers were further subjected to O-linked glycosylation and conversion from high mannose glycans to complex glycans followed by sialylation. Three species of dimers composed of 30K and 35K subunits were secreted into the culture supernatant as HBsAg particles. HBsAg was synthesized, glycosylated with both N- and O-linked glycans, sialylated, and then secreted into the culture supernatant within 1 h. These modifications of HBsAg by glycans might stabilize its structure and enhance its immunogenicity as a live HBV vaccine.

Evaluation of transcatheter arterial embolization with epirubicin-lipiodol emulsion for hepatocellular carcinoma

A total of 18 patients with hepatocellular carcinoma (HCC) were treated by transcatheter arterial embolization (TAE) with a 4'-epi-doxorubicin (EDX)-lipiodol emulsion. Infusion of the EDX-lipiodol emulsion (EDX-L) via the hepatic artery was followed by the injection of gelatin sponge in 12 cases. The response and survival of these 12 patients following EDX-L treatment were compared with those of 42 subjects treated with a doxorubicin-lipiodol emulsion (DX-L) and those of 23 patients treated by TAE with gelatin sponge (GS) only. In the group treated with EDX-L, nine cases were AFP-positive in sera and four showed a decrease in serum AFP values to less than 10% of the pretreatment level. Seven cases showed a partial response, and nine cases showed no change in the size of the tumor. In the group treated with EDX-L, nine cases are alive, and the oldest has survived for more than 431 days since the treatment. The half-year survival value was 57%, and the 1-year survival value was 49%. These values did not differ significantly from those calculated for the group treated with DX-L. The 1-year survival value determined for patients treated with a lipiodol emulsion (EDX-L or DX-L) followed by GS was 65%, and the 2-year survival value was 39%. These results rates are significantly better than those obtained in patients treated with GS only (1-year survival, 39%; 2-year survival, 13%.

Enhanced ATPase activity in liver cell nuclei induced by administration of mitomycin C to rats

Intraperitoneal administration of mitomycin C (40 micrograms/100 g body weight) to male Wistar rats increased the ATPase activity in hypotonic extracts of liver cell nuclei for 4 days after injection. Partially purified ATPase, obtained by the DEAE-cellulose column chromatography of these extracts, showed a 14 times higher specific activity than that found in normal rat liver nuclei. The enzymatic activity was strongly enhanced by the addition of polynucleotides, especially poly A and poly I, to the assay mixture, but was inhibited by GTP, a chelating agent, heparin and thiol-group inhibitors. Quercetin and oligomycin were less effective, and ouabain showed no inhibitory effect. Mg2+ ions were essential, but neither Ca2+, Na+ nor K+ ions were required for the manifestation of the activity. These characteristic properties of the enzyme are similar to those of a nucleoside triphosphatase found in the nuclear matrix and envelope, suggesting that some energy-providing mechanisms involved in the repair processes of DNA damage or cellular injury are induced by mitomycin C administration.

Hypomethylation of the c-myc oncogene in liver cirrhosis and chronic hepatitis

In order to investigate how chronic liver diseases, including liver cirrhosis and chronic hepatitis, are associate with hepatocarcinogenesis in terms of gene alteration, the methylation states of the c-myc and c-Ki-ras genes were examined in 34 liver tissues from patients with chronic liver disease without hepatocellular carcinoma (HCC), 34 non-tumor liver tissues from patients with HCC, 18 HCC tissues and 31 control liver tissues. The methylation states were analyzed by the Southern hybridization method using the restriction endonuclease isoschizomers MspI and HpaII. The CCGG sites at the second exon of the c-myc gene tended to be more extensively hypomethylated both in chronic liver disease and in non-tumor tissues than in control livers. Whereas the CCGG sites of the c-Ki-ras, and the third exon of the c-myc gene tended to be hypomethylated only in HCC tissues in comparison with other tissue groups. These results suggest that chronic liver disease may be situated between normal liver and HCC based on the state of DNA methylation and associated with the development of HCC through hypomethylation of the c-myc and/or c-Ki-ras gene.

Quantitative measurement of ultraviolet-induced damage in cellular DNA by an enzyme immunodot assay

A simple enzyme immunoassay procedure was developed for the quantitative determination of 254-nm uv-induced DNA damage in cells. With the use of specific antibodies to uv-irradiated DNA and horseradish peroxidase-conjugated antibody to rabbit IgG, the extent of damaged DNA in uv-irradiated rat spleen mononuclear cells was quantitatively measurable. Through the use of this method, the amount of damaged DNA present in 2 X 10(5) cells irradiated at a dose of 75 J/m2 was estimated to be 7 ng equivalents of the standard uv-irradiated DNA. In addition, when the cells, irradiated at 750 J/m2, were incubated for 1 h, the antigenic activity of DNA decreased by 40%, suggesting that a repair of the damaged sites in DNA had proceeded to some extent in the cells.

Production of 5-formyluracil from thymine in an in vitro active oxygen-generating system

Thymine was placed in a model active oxygen-generating system containing ferrous sulfate, EDTA, and ascorbic acid. The oxidative products of thymine were separated by Sephadex LH-20 chromatography and a reversed phase high-performance liquid chromatography (HPLC) into at least five major components. One of them had a UV spectrum characteristic of 5-formyluracil and mass spectrometric analysis of this material also indicated this material to be 5-formyluracil.